But the problem that I face now is how would I create sections within that void? So I have a Register username section and a Register password section within that void. Is there a way to split those sections up so that when I come to return an error I can do something like

Of course, from here you could do all sorts of fancy things, like keeping track of how many tries the user makes to register and then exiting. You could even return the value of the username and password and display them at the end of CallCommandRegister(), but I'll let you figure that one out. :)